Automatic pressure-controlled electric switch and air-gage.



No 850,081. PATENTED APR. 9, 1907.

L. H. WESTPI-IAL; AUTOMATIC PRESSURE CONT-ROLLED ELECTRIC SWITCH AND AIRGAGE.

APPLIGATION FILED OGT.3, 1905.

ivil/14mm:

g IL/M. 54 5 am sup ly of compressed fluid fa UNITED STATES PATENTOFFICE.

LOUIS H. wEsTPHAL, OF DAVENPORT, IOWA, ASSIGNOR To AUTOMATIC ELECTRICPUMP C MPANY; OF DAVENPORT, IOWA.

AUTOMATIC PRESSURE-CONTROLLED ELECTRIC SWITCH AND AIR-GAGE.

Specification'of Letters Patent. Application filed October 3,1905. s 'uNo. 281.123.

' Patented April 9, 1907.

of Davenport, in the county of Scott and- State of Iowa, haveinvented-certain new and useful Iin rovements in Automatic Pressure-Controlled Electric- Switch and AireGages; and 'I hereby declare thatthe following is a full, clear, and exact description thereof, referencebein' had to the accompanying drawings, whicIi form part of thisspecification.

This invention is an improvement in automatic pressure-controlledelectric switches and air-gages of the type shown in the patent to Pugh,No. 765,040, of July 12,- 1904. I

The device is particularly adapted for use in connection with electricalpumps for com pressing air or other fluids under pressure and isdesignedto throw the pumps into or out of action, according as theressure falls below or rises above the desire 'point, thus maintaining apractically uniform or constant pressure at all-times and economizingpower by only operating the pumps when the ls below the desire minimum.The objects of the present invention are to make the switch more-sensitive and certain I Y in action, to render it less liable to arc,and to have it close or 0 en the circuit with a snap m0t1on, so that wen the pressure rises above 'the desired point the circuit will bebroken instantaneously and if the pressure falls below the desired pointthe circuit will be closed instantaneously, thus reventing erratic anduncertain actions oi the electrical apparatus which controls theair-pressure also to prevent the air-gage from becomng charged withelectricity when the current 4 1's on.- .7 The invention will bethoroughlyunder- I stood from the following 'description of theapparatus, illustrated in the drawings, and "the novel features-aresummarized in the a claims.

Insaid drawings, Figure l is a rear view of the gage with cover removed,showing the operative parts controlling the electrical switch andshowing said switch closed in full linesand'open in dotted lines. Fig. 2is a detail sectionon line 2 2, Fig; 1. Fig. 3 is a detail sectionalview, enlarged, showing the con :struction of the contacts. Fig. 4isadiagram I of the complete apparatus, showing the electrical andpneumatic connections.

In the drawings, A designates a pneumatic or fluid-pressure indicator ofthe ordinag t pe, communicating with an air-reservoir through a pipe Rin the usual manner. so as to be subject to the pressure in thereservoir. In this indicator is a chamber B, which is in communicationwith the air-pipe R, and in' chamber B is a diaphragm b, pressed upon bya plungerC, attached to a stem 0, working in a'slotted cylinder C andpressed inward by a s ring C As these parts are substantially like thosedescribed in the aforesaid patent to Pugh and operated as described insaid patent, a detailed description and illustration thereof is notrequired hereim To the stem 0 of the plun er is attaohed a plate D bymeans of a screw which asses through a slot D in plate D, so as to alow' a certain adjustment of the plate on the stem. Plate D has twoupstanding fingers d and d, which embrace between them a block E ofinsulating material, fast onan arm E, secured atone end on a block F,which is pivotally attached to an insulated plate G (seicured in thecasing. of the ga e) by means of a screw F. The arm E at its e endisslotted to embrace the-beveled edge of an enlarges ment or'blook 11,attached to a sprin I, fixed to a bracket I, which bracket is ajustablIy attached to the plate Gby'means of a slot and screw I asshown. The enlargement i has a notch L in it, whichis ada ted to-beengaged b afriction-roller e in t e slotted end of arm when the switchis clos'edand hold the switch closed until the roller is forced out ofthe notch, as hereinafter described. The

rearward swing of the arm E is-limited .by a

bracket M, attached to theplate G by a screw M, as shown.

To the block F is also attached a brass spring e, which swings withthe-arm and has ,on its outer en'd a head e; to which is attached-aplatinum contact-strip 0 which is secured by placing its ends in opositely-inolined slots e in opposite sides OI .the head and then sueezing the sides of the head, so as to close the slots on the strip,thus fastenuslng solder'and forming a large contact surface. ,Theoposite contact-strip j isalso preferably ma e of platinum attached,

, ing the strip to the head without necessarily postK through wire K tospring 6 and conaccumulate against block E through finger to a bracketJ, adjustably secured to plate G by means of a bolt J, passing through aslot J in the bracket. This bracket J is prel'er ably of brass and isprovided with lugs on its' upper surface, between which the contact j"is placed and secured by bending down or closing over the lugs jthereon, as shown more clearly in Fig. 3 of the drawings.

One of the binding-posts K is connected by a wire K to the spring 0, thewire being preferably soldered to the spring, so that the current willnot ass to or through the pivotblock. The ot erbinding-post L is OOH,nected by a wire L to the bracket J, as shown. The circuit thereforewould be from tacts e f, brackets J, and wire L to post L, provided thecontacts are closed; but if they be separated of course the circuit isbroken, and no current would pass.

When the pressure in the reservoir R falls below the desired point, thes ring C will force the plunger C inward, ant in so doing finger (1 willengage block E and force arm E toward bracket M. The beveled edge ofblock 'i at this time, however, stands in the path of the armE and willobstruct the free swing of the latter, so that not until spring Cthrough finger d exerts sufficient pressure on arm E to cause it toovercome the resistance of spring I and force arm E outward until roller6 enters notch i/ will the contacts 0 7' be brought together; but when sring C does exert suflicient force to move ro ler 0* into notch i themovement occurs with a snap action, as is evident, and this movementcauses spring-arm e to move contact 6 quickly against contact j and holdsaid 0on tacts together, thus closing the circuit and keepingvit closeduntil the pressure in the reservoir and cylinder B rises sufficiently toovercome the resistance of spring C and moves the plunger outward untilfinger C! engages block E and tries to move the latter outward. Theoutward movement of the arm E, however, is opposed by spring I throughthe notch 7;, which is engaged by roller 6 on arm E, and thereforepressure will d until it is sufficient to snap roller e out of notch 'i,and when this occurs the contact e is instantly thrown away from contacty' and kept away from the latter by reason of the beveled edge of blocki engagingroller e Thus the circuit may be instantaneously broken andheld open until, the pressure in the reservoir falls so much that springC swings arm E back into engagement with notch i, as above described.

From the foregoing it will be seen that the switch is opened and closedinstantly with a snap action, thus avoiding thepossibility oi arcing;that the motors are caused to operate positively, if at all, and oneonly thrown into secpsi action when there is a sensible decrease in thepressure.

The spring I can be regulated by adjusting bracket 1 so that.- theamount of pressure necessary to snap arm E into or out of notch i can bemeasurably regulated thereby, as

well as by adjusting plate D on the stem and by adjusting the tension ofspring The bracket M prevents too great outward movement of the arm E.

The connection and operation of the parts with the motor-pumps andcompressors are shown diagrammatically in Fig. 4, in which R is thereservoir, connected by pipe S with the air-compressor T, which isoperated by an electric motor U, connected by wire 12 to one pole of theelectrical supply or generator V and by wire "0 to one pole K of thegage, the other pole L of which is connected by wire 1. to the otherpole of the generator V, thus completing the electrical circuit. Theparticular construction of the reservoir, pump, and generator are notclaimed herein, and they may and will be varied to suit the particularuser. 1

it will of course be understood that the invention is not limited to usein connection with air-compressors, but may be employed wherever it isdesired to control an electric circuit by a fluid-pressure gage.

Having thus described my invention, what I claim as new, and desire tosecure by Let ters Patent, is-

1. In a fiuid-controlled electric switch, the combination of a swingingarm, a contact connected with said arm, a fixed contact, a retainingdevice engaging the free end of said arm and adapted to hold it inclosed position, and means or positively actuating said arm in bothdirections against the resistance of the retaining device, said meansbeing controlled in one direction by fluid-pressure and in the oppositedirection by a spring.

2. In a pneumatically-controlled electric switch, the combination of apivoted swinging arm, a contact yieldingly connected, with the pivotedend of said arm, a fixed contact, a notched spring engaging the tree endof said arm and adapted to retain it in closed position, meanscontrolled in one direction by pneumatic pressure and in the oppositedirection by a spring for positively actuating said arm in bothdirections and overcoming the resistance of the spring, substantially asdescribed.

3. In combination, a pivoted block, an arm attached thereto, a springengaging the free end of said arm having a notch 'for locking said armin closed position, a movable contact connected ,to said block; a fixedcontact, a rod adapted to be moved in one direction by fluid-pressureand in the opposite direction by a spring; and lingers attached to saidrod and projecting on opposite sides of said arm, and adapted to move itagainst the resistance of said spring, substantially as described.

4. In combination, aswinging arm, a detainer-sp ring engaging said arm,a block on the deta1ner-spring for holdin said arm in closed position,aspring attache to said arm; a movable contact carried by said spring,and a fixed contact; with a reciprocating rod adapted to be moved in onedirection by fluid-pressure and in the opposite direction bya spring;and fingers attached to said rod and projecting on opposite sides ofsaid arm, and adapted to move the arm against the resistance of thedetainer-spring, substantially as described.

5. In a fluid-pressure electric switch, a pivoted arm, a movable contactyieldingly connected therewith; a fixed contact opposite said movablecontact; and a spring having a block thereon engaging the free end ofsaid arm to retain it in closed position; with a fluidpressure chamber,a plunger operated in one direction by the fluid-pressure, a spring forretracting said plunger, fin ers attached to said plunger, an insulatedb 'ock on said arm.

between said fingers whereby the switch is 'snapfped open when thepressure on the plune orces the arm out of the notch snapped closed whenarm into the notch.

and is the pressure forces the 6. In a pressure-controlled electricswitch,

the combination of a relatively fixed contact, a movable contact mountedon a spring, a pivoted block to which said spring is attached, an armattached to said block; a notched block adapted to engage the free endof said arm;a spring carrying said block; a reciprocating rod engagingan insulatingblock on said arm, a pneumatically-controlled plungeradapted to rection against theiresistance of the notched block, and aspring for moving the rod inthe opposite direction.

7. In a pressure-controlled electric switch, the combination of arelatively fixed contact, a movable contact mounted on a spr' g, apivoted arm to which said spring is attached; an adjustable springcarrying a notched block adapted to engage the free end of said arm; areci rocating rod, a pneumaticallycontrolled p unger adapted to movesaid rod in one direction, a spring for moving the rod in the oppositedirection; an insulated block attached to said arm, and fingers attachedto said rod and projecting on opposite sides of said insulated block,substantially as and for the slotted end of the arm, a

the purpose described.

8. The combination of a swinging arm having a'slotted end, a detainer-sring engaging iired contact, a movable contact connected with said arm,and means controlled in one direction by, fluidpressure, and inthe'opposite direction by a I necting said contacts to an with a movablestem adjacent the arm, a plate move said rod in one dispring foractuating said arm against the resistance of the detainer-spring,substantially as described.

9. The combination of a swinging arm having'a slotted end, a notcheddetainerspring engaging the slotted end of the arm, an insulated blockon the arm, a contact connected to said arm, a fixed contact; means forcon electric circuit;

attached to said stem engaging the block thereon; means for moving saidstem by pneumatic pressure in one direction, and a spring for moving thestem in the opposite direction whereby the resistance of thedetainer-spring may be overcome and the switch opened and closed,substantially as set forth.

10. Inan electric-switch contact, the com.

bination of a metal head with a platinum contact-piece having its endsfastened in slots or incisions in the sides of the head, substantiallyas shown and described. v 11. In an electric-switch, a contact-piececonsistin inclined s ots in its opposite sides, with-a contactiece ofplatinum underlying the head and aving its ends fastened in said slotsby swagin substantially as described.

12. n a fluid-controlled electric switch, the combination of a movablearm, a contact connected with said arm, a contact fixed relatively tothe arm, a spring engaging the free end of said arm and adapted toretain it in closed position, and means for positively actuating saidarm in both directions, said means being actuated in one direction byfluid-pressure and in the opposite direction by a s ring.

'13. n apneumatically-controlled electric switch, the combination of apivoted arm, a contact connected with said arm, a contact fixedrelativel to the arm, a notched spring engaging the ee end of said armand adapted to retain it in closed'position, and means actuated in onedirection by pneumatic ressure and in the opposite direction y a sprinfor positively actuating said arm in both directions.

14. In combination, a swinging arm, a spring enga 'ng said arm having anotch for locking sai arm in closed position, a movable contact carriedby fixed-relatively to the arm, a rod adapted to be moved in onedirection by fluid-pressure and in the opposite direction by a spring;and fingers attached to said rod and projecting on opposite sides ofsaid arm, for the purpose an substantially as described.

15. In combination, a swin g arm, a s ring engaging said arm, a note edblock on t e spring for locking said arm in closed posi tion, aspringattached to said arm and amat able contact carried by said spring; acontacli fixed relatively to said arm,.a reciprocating of a brass headhaving oppositelysaid arm; acontact IIO rod adapted to be moved in onedirection by fluid-pressure and in the opposite direction by a spring;and fingers attached to said rod and projecting on opposite sides ofsaid arm, for the purpose and substantially as described.

16. In a fluid-pressure electric switch, a pivoted arm, a movablecontact connected therewith; a fixed contact opposite said movablecontact; a spring having a notched block thereon engaging the free endof said arm to hold it in closed position; a fluid-pressure chamber, aplunger adapted to be operated in one direction by the fluidpressure, aspring for retracting said plunger, and devices attached to said plungeradapted to engage said arm on opposite sides, whereby the switch issnapped open when the pressure forces the arms out of the notch and issnapped closed When the spring forces the arm into the notch.

17. In apressure-controlled electric switch, the combination of a fixedcontact, a movable contact mounted on a spring, a swinging arm to whichsaid spring is attached; a notched block adapted to engage the free ii 1l b 1 end of said arm; a spring carrying said block; a reciprocating rodadapted to actuate said arm, a pneumatically controlled plunger adaptedto move said rod in one direction, and a spring for moying the rod inthe opposite direction. I

18. in combination, a swinging arm, a spring engaging said arm, anotched block on the spring for locking said arm in closed position, aspring attached to said arm and a movable contact carried by saidspring, a contact fixed relatively to said arm, a reciprocating rodadapted to be moved in one direction by fluid-pressure and in theopposite direction by a spring, a stop for limiting the spring-actuatedmovement of the rod, and fingers attached to said arm and projecting onopposite sides of said arm, for the purpose and substantially asdescribed.

In testimony that I claim the foregoing as my own i affix my signaturein presence of tvo Witnesses.

LOUlS H. NESTPHAL. In presence of- H. A. CARSTENS,

OTTO ELMEGREEN,

